Fraeman, Abigail A.

Caltech Authors - Main

 
 
 
 
 
 
 
 
 
 
 
 
 
 
W.M. Keck Institute for Space Studies 
Postdoctoral Fellowship Final Report 
 
Abigail Fraeman 
August 2014 – February 2016 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
W. M. Keck Institute Prize Postdoctoral Fellow Annual Report 
  2 
I. Introduction 
 
The W.M. Keck Institute for Space Studies Postdoctoral Fellowship provided me with 
an amazing opportunity to significantly advance both my research and career goals. 
Having the flexibility to design my own research program allowed me to tackle exciting, 
high risk-high reward scientific problems, which are described in more detail below. 
This freedom provided by the program also gave me the chance to develop my voice 
as an independent scientist.  
 
In addition to research, the KISS fellowship was also invaluable for allowing me to 
become part of a multidisciplinary community of extraordinary scientists and engineers. 
The people I met at KISS workshops, lectures, dinners, and other events cemented my 
connection between Caltech campus and JPL and helped me achieve my top career 
choice as a job as a JPL research scientist. 
 
II. Scope and aim of work 
 
1. Detailed coordinated orbital mapping of lower Mt. Sharp using next 
generation data products.  
 
Curiosity is currently exploring the lower flanks of Mt. Sharp – a 5 km high mound of 
sedimentary material in the center of Gale Crater.  Curiosity’s ground based 
explorations benefit greatly from synergistic analysis of orbital datasets, which provide 
a broad scale geologic context for Curiosity’s narrow focused observations and are 
also important for rover path planning to help locate the most efficient routes towards 
scientifically interesting targets.  
 
During my time as a KISS postdoc I generated a refined stratigraphy (mapping of rocks 
in time ordered depositional events) of Mt. Sharp.  This work was novel because I used 
newly derived, highest possible resolution data products that were generated with the 
help of several research collaborators.  These new orbital data products included 
thermal inertias which for the first time explicitly modeled Mt. Sharp’s large elevation 
and albedo variations in their derivations, a high resolution color mosaic made from 
careful spatial registration and scene to scene albedo normalizations of 13 HiRISE 
scenes, and visible short wavelength spectral data that had been collected using 
along-track oversampling and regularized to higher than nominal spatial resolution.  
This work was also novel because I performed qualitative cross comparisons of the 
datasets to extract additional information that only became apparent after the 
coordinated studies. 
 
The Mt. Sharp stratigraphic group consists of seven relatively planar units delineated 
by differences in texture, mineralogy, and thermophysical properties.   
Two additional units, distinguishable by unique morphology and high thermal inertia 
values, unconformably overlie the Mt. Sharp group, recording a period of substantial 
deposition and exhumation that followed the deposition and exhumation of the Mt. 
Sharp group.  Several spatially extensive silica deposits associated with veins and 
  3 
fractures show late stage silica enrichment within lower Mt. Sharp was pervasive.  At 
least two laterally extensive hematitic deposits are present at different stratigraphic 
intervals, and both are geometrically conformable with lower Mt. Sharp strata.  The 
occurrence of hematite at multiple stratigraphic horizons suggests redox interfaces 
were widespread in space and/or in time, and future measurements by the Mars 
Science Laboratory Curiosity rover will provide further insights into the depositional 
settings of these and other mineral phases. 
 
The results of this study were published in the Journal of Geophysical Research: 
Planets (Fraeman et al., 2016a), and this paper is appended to the end of this report. 
 
2. Exploring microimaging spectroscopy as a tool for planetary sample 
analyses. 
 
Microimaging spectroscopy is an emerging technique that can be to assess the 
composition of geological samples at the micrometer scale.  While this technique was 
initially developed for use on an arm mounted instrument on planetary missions, its 
ability to rapidly and non-destructively collect data on samples requiring little to no 
preparation makes it a potentially powerful analysis method in terrestrial laboratories.   
Additionally, microimaging spectroscopy provides a unique opportunity to link meter to 
kilometer scale orbital and telescopic spectral observations with the micrometer scale 
processes that may be affecting these large scale data. 
 
I explored this technique by analyzing a variety of samples, including altered basaltic 
drill cores, deep marine carbonates, and various classes of meteorites (Martian 
meteorites, carbonaceous chondrites, and the howardite, eucrite, and diogenite (HED) 
suite), and explored the datasets.  The HED meteorite suite in particular provided 
intriguing first results because the data had clear spectral signatures with deep 
absorption bands and were constrained to well-known and limited number of 
mineralogical components. These meteorite samples are also interesting to study in 
more detail because they have a known parent body (Vesta) that has already been 
investigated extensively by the Dawn spacecraft, and therefore provide a unique 
opportunity to explore spectral links from the micrometer to the orbital data scale. 
 
I was fortunate to be able to delve more deeply into the HED data with the help of an 
undergraduate summer student, Geraint Northwood-Smith.  Using a combination of 
manual and automated hyperspectral classification techniques, we identified four major 
spectral classes of materials based on VSWIR absorptions that include pyroxene, 
olivine, Fe-bearing feldspars, and glass-bearing/featureless materials. Although this 
project is still ongoing, the preliminary results already demonstrated microimaging 
spectroscopy is an effective method for rapidly and non-destructively characterizing 
small compositional variations of meteorite samples and for locating rare phases for 
possible follow-up investigation. Future work will include incorporating SEM/EDS 
results to quantify sources of spectral variability, systematic use of DEMUD machine-
learning algorithm to locate rare phases, and placing observations within a broader 
geologic framework of the differentiation and evolution of Vesta. 
  4 
 
The preliminary results of this work focusing on HED meteorites was presented at and 
published in the proceedings of the IEEE Workshop on Hyperspectral Image and 
Signal Processing Conference (Fraeman et al., 2016b), and the paper is appended to 
the end of this report. 
 
3. Curiosity mission activities.  
 
In addition to research, I also continued to participate as a member of the Curiosity 
Science team.  In this capacity I served in several tactical planning roles related to 
science plan development and path planning, presented results of my research at 
science team meetings, and helped contribute to general team science discussions.  I 
was also deeply involved with planning and execution of Curiosity’s multi-week science 
campaign in the Bagnold Dunes.  Finally, I wrote a proposal for and was awarded a 
NASA ROSES grant to continue my participation on the Curiosity science team as a 
Participating Scientist at the conclusion of my KISS postdoc. 
 
III. Publications and presentations 
 
First author peer reviewed publications: 
 
Fraeman, A., Ehlmann, B., Arvidson, R., Edwards, C., Grotzinger, J., Milliken, R., 
Quinn, D., and Rice, M.  2016a. “The Stratigraphy and Evolution of Lower Mt. Sharp 
from Spectral, Morphological, and Thermophysical Orbital Datasets,” JGR-Planets, in 
press. 
 
Fraeman, A., Ehlmann, B., Northwood-Smith, G., Liu, Y., Wadhwa, M., Greenberger, 
R. “Using VSWIR Microimaging Spectroscopy to Explore the Mineralogical Diversity of 
HED Meteorites,” 2016b. IEEE Workshop on Hyperspectral Image and Signal 
Processing. 
 
First author conference abstracts: 
 
Fraeman, A., Ehlmann, B., Northwood-Smith, G., Liu, Y., Wadhwa, M., Greenberger, 
R. “Exploring the Mineralogical Diversity of HED Meteorites with Microimaging VSWIR 
Spectroscopy,” poster presentation at LPSC (2016). 
 
Fraeman, A., Ehlmann, B., Arvidson, R., Edwards, C., Grotzinger, J., and Rice, M. “The 
Stratigraphy and Evolution of Lower Mt. Sharp from Spectral, Morphological, and 
Thermophysical Orbital Datasets,” oral presentation at LPSC (2016). 
 
Fraeman, A., Edwards, C., Ehlmann, B., Arvidson, R., Horgan, B., Rice, M. “A Detailed 
Investigation of Lower Mt. Sharp using Coordinated Orbital Datasets,” oral presentation 
at GSA Annual Meeting (2015). 
 
Fraeman, A., “Deciphering the History and Habitability of Gale Crater with Orbital and 
  5 
Rover Datasets,” oral presentation at 11th Recontres du Vietnam, Planetary Systems 
Conference (2015). 
 
Fraeman, A., Arvidson, R., Ehlmann, B., Bridges, N., Clark, B., Cousin, A., Des Marais, 
D., Gellert, R., Johnson, J., Lapotre, M., Schroder, S., Stein, N., Sullivan, R., 
Wellington, D., “Physical and Material Properties of Gale Crater Sandy Deposits: From 
Rocknest to Pahrump”, poster presentation at LPSC (2015). 
 
Fraeman, A., Edwards, C., Ehlmann, B., Arvidson, R., and Johnson, J., “Exploring 
Curiosity’s Future Path from Orbit: The View of Lower Mt. Sharp from Integrated 
CRISM, HiRISE, and THEMIS Datasets,” poster presentation at LPSC (2015). 
 
Fraeman, A., Edwards, C., Ehlmann, B., “Habitable Environments Preserved in Lower 
Mt. Sharp: Exploring Curiosity’s Future Path from Orbit,” poster presentation at 3rd ELSI 
International Symposium (2015). 
 
IV. Acknowledgments 
 
I would like to thank my postdoctoral supervisor Bethany Ehlmann for her many hours 
of fruitful discussion on the direction and results of this work, as well as general 
discussion about career advice and future research directions.  The entire Caltech 
GPS staff including Ulrika Terrones, Irma Black, and Marcia Hudson, seamlessly 
helped me with my administrative and travel questions, for which I am deeply grateful.  
Finally, I want to thank Michele Judd, Tom Prince, the KISS fellows, and KISS staff for 
providing me with this amazing opportunity and for welcoming me into the wonderful 
KISS community. 
 
 
 
 
 
 


W.M. Keck Institute for Space Studies Postdoctoral Fellowship Final Report

https://authors.library.caltech.edu/70840/1/AFraeman_KISS_Postdoc_Report.pdf

W.M. Keck Institute for Space Studies Postdoctoral Fellowship Final Report

Abstract

Similar works

Full text

Available Versions

Caltech Authors - Main